Twenty climate change activists were arrested after they blockaded Hartlepool nuclear power station.

Police were called after members of pressure group Reclaim Power blocked the main entrance of the power station, near Seal Sands, from 8am yesterday.

Using locks, metal pipes and other equipment activists laid across the main entrance and unfurled a large banner saying "No More", in response to Government and nuclear industry plans to build a new generation of nuclear power stations.

One protester, Sophie Stevens, 23, from Leeds, said police initially let the activists know they were breaking the law, but took no action. But at about 3.30pm a specialist cutting crew began cutting free those who had chained themselves.

Speaking earlier in the day, Sophie said: "It has all been very peaceful.

"The protesters have come here from across the country and come from a range of backgrounds."

Darren Locke, from Reclaim Power, said: "Nuclear power is not a solution to climate change. It produces deadly waste which remains radioactive for thousands of years. But we do have another option - to reduce our energy consumption, and to get the power we do need from clean, safe renewable sources like wind and solar."

The protest is one of a series of actions by Reclaim Power highlighting reliance on fossil fuels and the need to replace them with renewable energy. Organisers said other planned action included a protest at Drax power station, North Yorkshire.

Superintendent Steve Ashman said: "The group were given ample opportunity to protest in a lawful manner. They were warned of the consequences if they failed to clear what is an emergency access road to a nuclear power plant. They failed to do so and action had to be taken."

Those arrested were interviewed and released on police bail, the conditions being they are not allowed to enter Hartlepool and must keep away from all UK power plants.

A spokesman for the power station said: "British Energy respects and recognises people's right to protest about what is a vital issue and have no objection to peaceful and lawful demonstration. Our prime concern is to safeguard the personal safety of our staff, the power station and the protesters themselves and bring the incident to a safe conclusion."